This primitive temporal background, against which the laws operate, plays a crucial role within the primitivist framework, in particular when it comes to physical possibility, counterfactuals and explanatory power. The case of counterfactuals within the framework of Maudlin's primitivism is especially telling, since it heavily relies on the initial value formulation of fundamental laws. As an example, [1]} considers the following counterfactual statement: “If the bomb dropped on Hiroshima had contained titanium instead of uranium it would not have exploded.” The initial value formulation of the relevant laws and the corresponding temporal structure allows Maudlin to evaluate and to ground the truth value of this counterfactual through a three-step process ([1]}): “Step 1: choose a Cauchy surface that cuts through the actual world and that intersects the bomb about the time it was released from the plane. All physical magnitudes take some value on this surface. Step 2: construct a Cauchy surface just like the one in Step 1 save that the physical magnitudes are changed in this way: uranium is replaced with titanium in the bomb. Step 3: allow the laws to operate on this Cauchy surface with the new boundary values generating a new model. In that model, the bomb does not explode. Ergo (if we have got the laws right, etc.) the counterfactual is true.” The truth value of the counterfactual is grounded in the temporal (Cauchy) development (governed or produced by the laws) of the suitably modified Cauchy data (according to the antecedent of the counterfactual). So, the temporal background—the temporal structure of the initial value formulation—is clearly playing an important role here in the work done by the laws (the importance of this role is nicely illustrated within the framework of Maudlin's primitivism, but we take our considerations above to suggest that the situation is similar in this respect in the case of dispositionalism, at least when it comes to fundamental dispositional properties).
